1. Field of the Invention
The present invention relates to a reverberation suppressing apparatus and a reverberation suppressing method.
2. Description of the Related Art
A reverberation suppressing process is an important technology used as a pre-process of auto-speech recognition, aiming at improvement of articulation in a teleconference call or a hearing aid and improvement of a recognition rate of auto-speech recognition used for speech recognition in a robot (robot hearing sense). In the reverberation suppressing process, reverberation is suppressed by calculating a reverberation component from an acquired sound signal every predetermined frames and by removing the calculated reverberation component from the acquired sound signal (see, for example, Unexamined Japanese Patent Application, First Publication No. H09-261133 (Patent Document 1)).
As a reverberation suppressing technology using an independent component analysis (ICA), a technology of updating a filter with a step size fixed has been suggested (for example, Ryu Takeda, Kazuhiro Nakadai, Kaznori Komatani, Tetsuya Ogata, and Hiroshi Okano, “Evaluation of Barge-in allowability using MFT and ICA for Conversation with Robot”, Information Processing Society, 70-th National Convention of Information Processing Society, 2008, p2-135 (Non-patent Document 1)). In addition, a technology of updating a filter by adaptively changing a step size has been suggested as the reverberation suppressing technology using an independent component analysis (see, for example, Unexamined Japanese Patent Application, First Publication No. 2008-306712 (Patent Document 2)).